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Ring Main Wiring
I have two ring mains, (downstairs and upstairs) both fed from 32A MCBs
in the consumer unit. The 'downstairs' MCB has three live connections, so I assume there's a spur somewhere ? I wish to add a small ring of 13A sockets (6 x 13A double sockets) in a new conservatory. As the downstairs ring is rather busy with kitchen appliances etc, I am planning to add this new ring to the 'upstairs' MCB. A: Can I do this ? B: Can I take a 6.0mm T&E from the consumer unit to the conservatory, and connect the other end to the new 2.5mm ring closer to the conservatory ? TIA -- Mark Please replace invalid and invalid with gmx and net to reply. |
On Sat, 05 Mar 2005 21:03:17 +0000, Mark Carver
strung together this: I have two ring mains, (downstairs and upstairs) both fed from 32A MCBs in the consumer unit. The 'downstairs' MCB has three live connections, so I assume there's a spur somewhere ? Sounds like it. I wish to add a small ring of 13A sockets (6 x 13A double sockets) in a new conservatory. As the downstairs ring is rather busy with kitchen appliances etc, I am planning to add this new ring to the 'upstairs' MCB. A: Can I do this ? Depends on the floor area. For a 32A ring circuit you should not be supplying more than 100m^2. B: Can I take a 6.0mm T&E from the consumer unit to the conservatory, and connect the other end to the new 2.5mm ring closer to the conservatory ? No. If you are going to add extra sockets to an existing ring then you need to extend the ring through the new sockets. You can either do this from an existing socket in the house or from the CU but you need to 'divert' one leg of the ring through the new sockets. However, this is all covered by Part P as it's a reasonably major project so you should be NICEIC registered to carry out this, you don't sound very NICEIC like? -- SJW Please reply to group or use 'usenet' in email subject |
On Sat, 5 Mar 2005 21:50:18 UTC, Lurch
wrote: However, this is all covered by Part P as it's a reasonably major project so you should be NICEIC registered to carry out this, you don't sound very NICEIC like? Some might argue that he does... -- Bob Eager begin a new life...dump Windows! |
On 5 Mar 2005 22:33:43 GMT, "Bob Eager" strung
together this: However, this is all covered by Part P as it's a reasonably major project so you should be NICEIC registered to carry out this, you don't sound very NICEIC like? Some might argue that he does... I did think that as I was typing the response. ;-) -- SJW Please reply to group or use 'usenet' in email subject |
Lurch wrote:
However, this is all covered by Part P as it's a reasonably major project so you should be NICEIC registered to carry out this Or not, if he does it on a building notice... (or ignores part P altogether ;-) -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
Lurch wrote:
On Sat, 05 Mar 2005 21:03:17 +0000, Mark Carver strung together this: I wish to add a small ring of 13A sockets (6 x 13A double sockets) in a new conservatory. As the downstairs ring is rather busy with kitchen appliances etc, I am planning to add this new ring to the 'upstairs' MCB. A: Can I do this ? Depends on the floor area. For a 32A ring circuit you should not be supplying more than 100m^2. That's OK then. The entire house is 120 m^2 (served by two 32A circuits), so upstairs will be 60ish. The conservatory is 14m^2. B: Can I take a 6.0mm T&E from the consumer unit to the conservatory, and connect the other end to the new 2.5mm ring closer to the conservatory ? No. If you are going to add extra sockets to an existing ring then you need to extend the ring through the new sockets. You can either do this from an existing socket in the house or from the CU but you need to 'divert' one leg of the ring through the new sockets. So I need to 'break and loop' into the existing 'downstairs' ring, and take that through the conservatory ? Just to confirm, I can't run two rings from one 32A MCB ? (which was what I was getting at) However, this is all covered by Part P as it's a reasonably major project so you should be NICEIC registered to carry out this, you don't sound very NICEIC like? I'm not, and what's Part P? ;-) -- Mark Please replace invalid and invalid with gmx and net to reply. |
"Mark Carver" wrote in message ... Lurch wrote: On Sat, 05 Mar 2005 21:03:17 +0000, Mark Carver strung together this: I wish to add a small ring of 13A sockets (6 x 13A double sockets) in a new conservatory. As the downstairs ring is rather busy with kitchen appliances etc, I am planning to add this new ring to the 'upstairs' MCB. A: Can I do this ? Depends on the floor area. For a 32A ring circuit you should not be supplying more than 100m^2. That's OK then. The entire house is 120 m^2 (served by two 32A circuits), so upstairs will be 60ish. The conservatory is 14m^2. B: Can I take a 6.0mm T&E from the consumer unit to the conservatory, and connect the other end to the new 2.5mm ring closer to the conservatory ? No. If you are going to add extra sockets to an existing ring then you need to extend the ring through the new sockets. You can either do this from an existing socket in the house or from the CU but you need to 'divert' one leg of the ring through the new sockets. So I need to 'break and loop' into the existing 'downstairs' ring, and take that through the conservatory ? Just to confirm, I can't run two rings from one 32A MCB ? (which was what I was getting at) However, this is all covered by Part P as it's a reasonably major project so you should be NICEIC registered to carry out this, you don't sound very NICEIC like? A DIYer can replace parts of a ring, but not install a new one. I'm not sure where extending comes into it. I'm not, and what's Part P? ;-) Do a Google with Part P in the subject line on this ng. _________________________________________ Usenet Zone Free Binaries Usenet Server More than 120,000 groups Unlimited download http://www.usenetzone.com to open account |
Doctor Evil wrote:
"Mark Carver" wrote in message I'm not, and what's Part P? ;-) Do a Google with Part P in the subject line on this ng. You didn't spot my winking smiley Doctor ! -- Mark Please replace invalid and invalid with gmx and net to reply. |
Mark Carver wrote:
Lurch wrote: I wish to add a small ring of 13A sockets (6 x 13A double sockets) in a new conservatory. As the downstairs ring is rather busy with kitchen appliances etc, I am planning to add this new ring to the 'upstairs' MCB. A: Can I do this ? you can do whatever you want. How you do it would determine whether its reg compliant. And I spose whether it would melt and catch fire or not. In principle its doable compliantly. Depends on the floor area. For a 32A ring circuit you should not be supplying more than 100m^2. That's OK then. The entire house is 120 m^2 (served by two 32A circuits), so upstairs will be 60ish. The conservatory is 14m^2. B: Can I take a 6.0mm T&E from the consumer unit to the conservatory, and connect the other end to the new 2.5mm ring closer to the conservatory ? it wont be compliant though. If you do it that way, better to make it a radial circuit. And why 6mm? NT |
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In article ,
Mark Carver wrote: I can easily break into the upstairs ring, and include the conservatory on this. From a common seance/Ohm's law perspective this is bad as it increases the loop resistance of that circuit. I return to the question posted at 08:50hrs, can I (regs wise) connect two radial circuits to one 32A MCB ? The load on that MCB will be exactly the same as if I were to break into the existing ring. Why not just change the CU for a suitable one with more ways? If it's reasonably recent, you should be able to re-use the existing MCBs and just add to them. A basic empty CU is pretty cheap. -- *If love is blind, why is lingerie so popular? * Dave Plowman London SW To e-mail, change noise into sound. |
Mark Carver wrote:
So I need to 'break and loop' into the existing 'downstairs' ring, and Yes take that through the conservatory ? Just to confirm, I can't run two rings from one 32A MCB ? (which was what I was getting at) No. You can run a spur from a ring circuit, and it is legitimate to have the spur originate at the CU if required. Unless separately fused however you would only be able to supply a single outlet on that spur. Running two ring circuits from a single MCB would not be not common practice... with a bit of luck someone will be along shortly to quote you the regs reference ;-) Do you not have a spare way on the CU? Since that would be the preferable place to run either a new ring circuit for the conservatory, or a radial if that would be simpler. -- Cheers, John. /================================================== ===============\ | Internode Ltd - http://www.internode.co.uk | |-----------------------------------------------------------------| | John Rumm - john(at)internode(dot)co(dot)uk | \================================================= ================/ |
John Rumm wrote:
Mark Carver wrote: So I need to 'break and loop' into the existing 'downstairs' ring, and Yes take that through the conservatory ? Just to confirm, I can't run two rings from one 32A MCB ? (which was what I was getting at) No. Interesting You can run a spur from a ring circuit, and it is legitimate to have the spur originate at the CU if required. Unless separately fused however you would only be able to supply a single outlet on that spur. Running two ring circuits from a single MCB would not be not common practice... with a bit of luck someone will be along shortly to quote you the regs reference ;-) Do you not have a spare way on the CU? Since that would be the preferable place to run either a new ring circuit for the conservatory, or a radial if that would be simpler. There are no spare slots in the CU, see:- http://www.mark.carver.dsl.pipex.com/cu.jpg (132k jpg) It's as old as the house, (20 years). The 16A breaker feeds an (emergency only) immersion heater. Could I upgrade that breaker to 32A (assuming suitable MCBs still exist for my model of CU ?) and run the new ring main from there, making the immersion heater effectively a spur ? -- Mark Please replace invalid and invalid with gmx and net to reply. |
"Mark Carver" wrote in message ... John Rumm wrote: Mark Carver wrote: So I need to 'break and loop' into the existing 'downstairs' ring, and Yes take that through the conservatory ? Just to confirm, I can't run two rings from one 32A MCB ? (which was what I was getting at) No. Interesting You can run a spur from a ring circuit, and it is legitimate to have the spur originate at the CU if required. Unless separately fused however you would only be able to supply a single outlet on that spur. Running two ring circuits from a single MCB would not be not common practice... with a bit of luck someone will be along shortly to quote you the regs reference ;-) Do you not have a spare way on the CU? Since that would be the preferable place to run either a new ring circuit for the conservatory, or a radial if that would be simpler. There are no spare slots in the CU, see:- http://www.mark.carver.dsl.pipex.com/cu.jpg (132k jpg) By rights you should upgrade the CU as all downstairs skts should be protected by a 32mA MCB It's as old as the house, (20 years). The 16A breaker feeds an (emergency only) immersion heater. Could I upgrade that breaker to 32A (assuming suitable MCBs still exist for my model of CU ?) and run the new ring main from there, making the immersion heater effectively a spur ? -- Mark Please replace invalid and invalid with gmx and net to reply. |
By rights you should upgrade the CU as all downstairs skts should be protected by a 32mA MCB Bloody hell, he wont run much on that !!! Dave -- For what we are about to balls up may common sense prevent us doing it again in the future!! |
On Sun, 06 Mar 2005 08:50:29 +0000, Mark Carver
strung together this: So I need to 'break and loop' into the existing 'downstairs' ring, and take that through the conservatory ? Yes. Just to confirm, I can't run two rings from one 32A MCB ? (which was what I was getting at) No, one 32A MCB, one ring. However, this is all covered by Part P as it's a reasonably major project so you should be NICEIC registered to carry out this, you don't sound very NICEIC like? I'm not, and what's Part P? ;-) Amusing. -- SJW Please reply to group or use 'usenet' in email subject |
On Sun, 6 Mar 2005 13:42:45 -0000, "Dave Jones"
strung together this: By rights you should upgrade the CU as all downstairs skts should be protected by a 32mA MCB I assume you mean a 30mA RCD? If so, incorrect. Being pedantic, socket outlets used to provide power to portable equipment used outdoors require RCD protection, this may or not be the downstairs ring circuit, and even then you may not need all the socket outlets to be protected. -- SJW Please reply to group or use 'usenet' in email subject |
Mark Carver wrote:
I have two ring mains, (downstairs and upstairs) both fed from 32A MCBs in the consumer unit. The 'downstairs' MCB has three live connections, so I assume there's a spur somewhere ? I wish to add a small ring of 13A sockets (6 x 13A double sockets) in a new conservatory. As the downstairs ring is rather busy with kitchen appliances etc, I am planning to add this new ring to the 'upstairs' MCB. A: Can I do this ? B: Can I take a 6.0mm T&E from the consumer unit to the conservatory, and connect the other end to the new 2.5mm ring closer to the conservatory ? TIA To deal with the Upstairs ring aspect. I wouldn't. If you, or one of yours, or a future owner were to have a fault, trip the breaker for downstairs and then fry, you would feel responsible? In a conservatory, I would be especially keen to have an RCD on the circuit. |
Andrew Chesters wrote:
To deal with the Upstairs ring aspect. I wouldn't. If you, or one of yours, or a future owner were to have a fault, trip the breaker for downstairs and then fry, you would feel responsible? I don't understand ? You mean switching off the downstairs breaker assuming it fed the conservatory, then electrocuting themselves ? If so I'd label the CU accordingly. In a conservatory, I would be especially keen to have an RCD on the circuit. As you can see from my photo the entire house is protected by an RCD, although it's an 80mA device. Anyway it looks as if I'm heading towards a complete CU replacement. It seems that my present breakers are BS 3871, doing some Googling these were withdrawn in 1994. I can't find any suppliers that do replacements ? Of course replacing the CU, would require getting the lekky board to come and remove their main 100A fuse, what can of worms does that open ? -- Mark Please replace invalid and invalid with gmx and net to reply. |
"Lurch" wrote in message ... On Sat, 05 Mar 2005 21:03:17 +0000, Mark Carver strung together this: I have two ring mains, (downstairs and upstairs) both fed from 32A MCBs in the consumer unit. The 'downstairs' MCB has three live connections, so I assume there's a spur somewhere ? Sounds like it. Might not be. When we tended to have smaller CUs it was quite common to run three wires from the CU through sockets in various directions and join them all together at some remote point so that all sockets had dual routing. Not sure if this is still allowed in the latest wiring regs though. |
"Dave Jones" wrote in message news:422b08ce$1_1@mk-nntp- take that through the conservatory ? Just to confirm, I can't run two rings from one 32A MCB ? (which was what I was getting at) By rights you should upgrade the CU as all downstairs skts should be protected by a 32mA MCB Presuming you mean 32A that isn't correct. It is (or at least used to be - haven't read the regs recently) quite acceptable to deliberately fit a smaller MCB on rings where it is known such a load would never be applied. |
On Sun, 06 Mar 2005 18:47:42 +0000, Andrew Chesters
strung together this: To deal with the Upstairs ring aspect. I wouldn't. If you, or one of yours, or a future owner were to have a fault, trip the breaker for downstairs and then fry, you would feel responsible? I certainly wouldn't. If some clueless ****wit fried themselves because they didn't know what they were doing and 'assumed' things relating to safety then it would not be anyones problem other than their own. In a conservatory, I would be especially keen to have an RCD on the circuit. Why's that then? -- SJW Please reply to group or use 'usenet' in email subject |
On Sun, 06 Mar 2005 19:04:31 +0000, Mark Carver
strung together this: As you can see from my photo the entire house is protected by an RCD, although it's an 80mA device. Nope, i't's an 80A 100mA device. Anyway it looks as if I'm heading towards a complete CU replacement. It seems that my present breakers are BS 3871, doing some Googling these were withdrawn in 1994. I can't find any suppliers that do replacements ? I've got some second hand ones. BS60898 is the replacement for BS 3871. Of course replacing the CU, would require getting the lekky board to come and remove their main 100A fuse, what can of worms does that open ? Looking at the picture of your CU the third wire in the existing ring main MCB is not a spur to a socket. It looks like the cooker cable has been moved across so that the new 6mm, (the cable with the white sheath), can be fitted to the now spare MCB. I would suggest that you call someone in to do all of this as some of your comments here scare me a little and show a lack of understanding. -- SJW Please reply to group or use 'usenet' in email subject |
Lurch wrote:
On Sun, 06 Mar 2005 18:47:42 +0000, Andrew Chesters strung together this: To deal with the Upstairs ring aspect. I wouldn't. If you, or one of yours, or a future owner were to have a fault, trip the breaker for downstairs and then fry, you would feel responsible? I certainly wouldn't. If some clueless ****wit fried themselves because they didn't know what they were doing and 'assumed' things relating to safety then it would not be anyones problem other than their own. In a conservatory, I would be especially keen to have an RCD on the circuit. Why's that then? Cables likely to be taken outdoors, moisture (Perhaps) maybe lots of potted plants in front of sockets... Not all a "regulation" reason, but just an instinct that the risks COULD be higher. |
On Sun, 6 Mar 2005 20:36:19 -0000, "Mike" strung
together this: I have two ring mains, (downstairs and upstairs) both fed from 32A MCBs in the consumer unit. The 'downstairs' MCB has three live connections, so I assume there's a spur somewhere ? Sounds like it. Might not be. When we tended to have smaller CUs it was quite common to run three wires from the CU through sockets in various directions and join them all together at some remote point so that all sockets had dual routing. Er, sounds a bit Heath Robinson, like. Think you'd better just observe this thread and try not to partake. Having a rough stab at something that might resemble the correct answer is not a good idea. If you read the rest of the thread you will find it is not as it seems anyway. Not sure if this is still allowed in the latest wiring regs though. Hopefully not. -- SJW Please reply to group or use 'usenet' in email subject |
In article ,
Mark Carver wrote: Of course replacing the CU, would require getting the lekky board to come and remove their main 100A fuse, what can of worms does that open ? Don't bother. Simply cut the seals and remove the fuse(s). Same with the meter if you need to replace the tails. They'll only be interested if your metered consumption - ie bills - suddenly drop enormously. But write and tell them you've cut them if you're worried. -- *Geeks shall inherit the earth * Dave Plowman London SW To e-mail, change noise into sound. |
"Lurch" wrote in message ... On Sun, 6 Mar 2005 20:36:19 -0000, "Mike" strung together this: I have two ring mains, (downstairs and upstairs) both fed from 32A MCBs in the consumer unit. The 'downstairs' MCB has three live connections, so I assume there's a spur somewhere ? Sounds like it. Might not be. When we tended to have smaller CUs it was quite common to run three wires from the CU through sockets in various directions and join them all together at some remote point so that all sockets had dual routing. Er, sounds a bit Heath Robinson, like. Possibly. But as I said this was a common approach to wiring in the 70s and could be what the OP has. |
Lurch wrote:
On Sun, 06 Mar 2005 19:04:31 +0000, Mark Carver strung together this: As you can see from my photo the entire house is protected by an RCD, although it's an 80mA device. Nope, i't's an 80A 100mA device. So it is, I shouldn't post from memory ! Anyway it looks as if I'm heading towards a complete CU replacement. It seems that my present breakers are BS 3871, doing some Googling these were withdrawn in 1994. I can't find any suppliers that do replacements ? I've got some second hand ones. BS60898 is the replacement for BS 3871. I've found this lot.... http://www.thefusecompany.com/ ......might do them, I'll give them a ring. Of course replacing the CU, would require getting the lekky board to come and remove their main 100A fuse, what can of worms does that open ? Looking at the picture of your CU the third wire in the existing ring main MCB is not a spur to a socket. It looks like the cooker cable has been moved across so that the new 6mm, (the cable with the white sheath), can be fitted to the now spare MCB. Investigating further the 4mm cable seems to feed a fused switch that in turn feeds the garage (detached from the house). I would suggest that you call someone in to do all of this as some of your comments here scare me a little and show a lack of understanding. Thank you for your concern, I might well do that. I'm an electronics/comms engineer, not electrical, but I'm well aware of the dangers, hazards, and issues involved, (that why I've asked in here) Thanks for all the responses. -- Mark Please replace invalid and invalid with gmx and net to reply. |
A DIYer can replace parts of a ring, but not install a new one. I'm not
sure where extending comes into it. A DIYer can do what they like. However, the extent of the work comes under Part P, which will require a building notice (and hence inspection) to remain legal. Christian. |
In the op's position, I would replace the CU with a larger split load
model and add some extra circuits. If it's easy to do so, I would find out what was and wasn't "ring" on the downstairs 32A breaker, and if it looks like a radial circuit has been added to it, move this onto it's own 20A breaker. Alternatively, depending how much load the OP expects to place on the conservatory circuit, he could use the esisting breaker marked Immersion heater to feed it as a radial rather than a ring, and either; 1. Forget about immersion heating. 2. (Getting non complient here) put the immersion heater on an fcu on the upstairs ring (assuming the cylinder is upstairs). 3. (getting even further away from compliance perhaps) leave it on the same breaker as the new radial. As long as he doesn't put a 3KW heater on the radial at the same time as the immersion is on, it shouldn't matter. |
Zikki Malambo wrote:
In the op's position, I would replace the CU with a larger split load model and add some extra circuits. If it's easy to do so, I would find out what was and wasn't "ring" on the downstairs 32A breaker, and if it looks like a radial circuit has been added to it, move this onto it's own 20A breaker. Alternatively, depending how much load the OP expects to place on the conservatory circuit, he could use the esisting breaker marked Immersion heater to feed it as a radial rather than a ring, and either; 1. Forget about immersion heating. In reality the actual immersion heater is not connected to anything ! The previous owners 'stole' its feed, and connected that to a shower pump, (100 watts) 2. (Getting non complient here) put the immersion heater on an fcu on the upstairs ring (assuming the cylinder is upstairs). Yes, as you say not allowed. Such devices cannot be fed as spurs off of ring circuits AIUI ? What I could do is move the pump to a ring main spur, and stick a 13A flying lead and plug on the immersion heater (not allowed according to regs), or as you say totally forget the immersion heater. Then I just replace the existing 16A breaker with a 32A and feed the conservatory as a ring circuit off this. 3. (getting even further away from compliance perhaps) leave it on the same breaker as the new radial. As long as he doesn't put a 3KW heater on the radial at the same time as the immersion is on, it shouldn't matter. A 3kW load in the conservatory is very likely :-( -- Mark Please replace invalid and invalid with gmx and net to reply |
Mark Carver wrote:
It's as old as the house, (20 years). The 16A breaker feeds an (emergency only) immersion heater. Could I upgrade that breaker to 32A (assuming suitable MCBs still exist for my model of CU ?) and run the new ring main from there, making the immersion heater effectively a spur ? The proper answer is no: fixed water heaters should have their own dedicated final circuit; this is a clear requirement of the Regs. The pragmatic view is that IF you're accumulating tuits to fit a bigger CU, AND you can be SURE the immersion won't be used other than in the case of a boiler breakdown, AND you can be sure no-one else in the household will violate that assumption, AND you'll restore to fully compliant before you sell, you won't in fact be creating anything actively dangerous. At least, that appears to have been the reasoning of the professional electrician who ran out of ways on the CU in this place after putting in a new ring for the garage conversion - having I assume consulted with the previous owners, the upstairs ring was chosen as the one to sneakily add the only-in-emergency immersion to... Going back to your actual requirement - one other perfectly reasonable solution is to run your conservatory sockets as a *fused* spur from a nearby point on the ring. 13A should be plenty for the conservatory's requirement - a coupla lamps, boombox, fanheater in exceptional circs. Stick the FCU - switched or unswitched - next to the socket you're teeing off, consider using one which comes with an RCD if the downstairs sockets aren't already RCD'd (wot with conservatories being semi-outdoor), label the FCU neatly, campers of happpiness all round. Stefek |
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